rule win_slowstepper_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.slowstepper."
        info = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator v0.6.0"
        signator_config = "callsandjumps;datarefs;binvalue"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.slowstepper"
        malpedia_rule_date = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        malpedia_license = "CC BY-SA 4.0"
        malpedia_sharing = "TLP:WHITE"

    /* DISCLAIMER
     * The strings used in this rule have been automatically selected from the
     * disassembly of memory dumps and unpacked files, using YARA-Signator.
     * The code and documentation is published here:
     * https://github.com/fxb-cocacoding/yara-signator
     * As Malpedia is used as data source, please note that for a given
     * number of families, only single samples are documented.
     * This likely impacts the degree of generalization these rules will offer.
     * Take the described generation method also into consideration when you
     * apply the rules in your use cases and assign them confidence levels.
     */


    strings:
        $sequence_0 = { 0fbe4808 83e900 745a 49 7461 49 745e }
            // n = 7, score = 100
            //   0fbe4808             | movsx               ecx, byte ptr [eax + 8]
            //   83e900               | sub                 ecx, 0
            //   745a                 | je                  0x5c
            //   49                   | dec                 ecx
            //   7461                 | je                  0x63
            //   49                   | dec                 ecx
            //   745e                 | je                  0x60

        $sequence_1 = { 8955fc 8d4e34 6a0f c706???????? 58 894114 895110 }
            // n = 7, score = 100
            //   8955fc               | mov                 dword ptr [ebp - 4], edx
            //   8d4e34               | lea                 ecx, [esi + 0x34]
            //   6a0f                 | push                0xf
            //   c706????????         |                     
            //   58                   | pop                 eax
            //   894114               | mov                 dword ptr [ecx + 0x14], eax
            //   895110               | mov                 dword ptr [ecx + 0x10], edx

        $sequence_2 = { 885dfc e8???????? 834dfcff 6a01 8db5c8fdffff e8???????? 32c0 }
            // n = 7, score = 100
            //   885dfc               | mov                 byte ptr [ebp - 4], bl
            //   e8????????           |                     
            //   834dfcff             | or                  dword ptr [ebp - 4], 0xffffffff
            //   6a01                 | push                1
            //   8db5c8fdffff         | lea                 esi, [ebp - 0x238]
            //   e8????????           |                     
            //   32c0                 | xor                 al, al

        $sequence_3 = { 894304 8b4704 894308 33c0 8d7b10 8945fc 895dec }
            // n = 7, score = 100
            //   894304               | mov                 dword ptr [ebx + 4], eax
            //   8b4704               | mov                 eax, dword ptr [edi + 4]
            //   894308               | mov                 dword ptr [ebx + 8], eax
            //   33c0                 | xor                 eax, eax
            //   8d7b10               | lea                 edi, [ebx + 0x10]
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   895dec               | mov                 dword ptr [ebp - 0x14], ebx

        $sequence_4 = { c7830408000015000000 59 be???????? 8d7b04 f3a5 }
            // n = 5, score = 100
            //   c7830408000015000000     | mov    dword ptr [ebx + 0x804], 0x15
            //   59                   | pop                 ecx
            //   be????????           |                     
            //   8d7b04               | lea                 edi, [ebx + 4]
            //   f3a5                 | rep movsd           dword ptr es:[edi], dword ptr [esi]

        $sequence_5 = { ab 66ab 53 aa 8d8530f5ffff 50 6a18 }
            // n = 7, score = 100
            //   ab                   | stosd               dword ptr es:[edi], eax
            //   66ab                 | stosw               word ptr es:[edi], ax
            //   53                   | push                ebx
            //   aa                   | stosb               byte ptr es:[edi], al
            //   8d8530f5ffff         | lea                 eax, [ebp - 0xad0]
            //   50                   | push                eax
            //   6a18                 | push                0x18

        $sequence_6 = { 68???????? 8bfa 56 8975cc 897dc8 e8???????? 895dfc }
            // n = 7, score = 100
            //   68????????           |                     
            //   8bfa                 | mov                 edi, edx
            //   56                   | push                esi
            //   8975cc               | mov                 dword ptr [ebp - 0x34], esi
            //   897dc8               | mov                 dword ptr [ebp - 0x38], edi
            //   e8????????           |                     
            //   895dfc               | mov                 dword ptr [ebp - 4], ebx

        $sequence_7 = { 889c241c010000 8dbc241d010000 ab ab ab ab }
            // n = 6, score = 100
            //   889c241c010000       | mov                 byte ptr [esp + 0x11c], bl
            //   8dbc241d010000       | lea                 edi, [esp + 0x11d]
            //   ab                   | stosd               dword ptr es:[edi], eax
            //   ab                   | stosd               dword ptr es:[edi], eax
            //   ab                   | stosd               dword ptr es:[edi], eax
            //   ab                   | stosd               dword ptr es:[edi], eax

        $sequence_8 = { 837de802 7ccb 47 33f6 eb9f ff75e4 c745e001000000 }
            // n = 7, score = 100
            //   837de802             | cmp                 dword ptr [ebp - 0x18], 2
            //   7ccb                 | jl                  0xffffffcd
            //   47                   | inc                 edi
            //   33f6                 | xor                 esi, esi
            //   eb9f                 | jmp                 0xffffffa1
            //   ff75e4               | push                dword ptr [ebp - 0x1c]
            //   c745e001000000       | mov                 dword ptr [ebp - 0x20], 1

        $sequence_9 = { 8db43e9979825a 8b7b28 8975ec 8bf7 c1c618 23f2 c1c708 }
            // n = 7, score = 100
            //   8db43e9979825a       | lea                 esi, [esi + edi + 0x5a827999]
            //   8b7b28               | mov                 edi, dword ptr [ebx + 0x28]
            //   8975ec               | mov                 dword ptr [ebp - 0x14], esi
            //   8bf7                 | mov                 esi, edi
            //   c1c618               | rol                 esi, 0x18
            //   23f2                 | and                 esi, edx
            //   c1c708               | rol                 edi, 8

    condition:
        7 of them and filesize < 909312
}